When people suffer from some types of heart arrhythmias, the result may be that blood flow to various parts of the body is reduced. Some arrhythmias may even result in a Sudden Cardiac Arrest (SCA). SCA can lead to death very quickly, e.g. within 10 minutes, unless treated in the interim.
Some people have an increased risk of SCA. People at a higher risk include individuals who have had a heart attack, or a prior SCA episode. A frequent recommendation is for these people to receive an Implantable Cardioverter Defibrillator (“ICD”). The ICD is surgically implanted in the chest, and continuously monitors the person's electrocardiogram (“ECG”). If certain types of heart arrhythmias are detected, then the ICD delivers an electric shock through the heart.
After being identified as having an increased risk of an SCA, and before receiving an ICD, these people are sometimes given a wearable cardiac defibrillator (“WCD”) system. A WCD system typically includes a harness, vest, or other garment that the patient is to wear. The WCD system includes a defibrillator and electrodes, coupled to the harness, vest, or other garment. When the patient wears the WCD system, the external electrodes may then make good electrical contact with the patient's skin, and therefore can help determine the patient's ECG. If a shockable heart arrhythmia is detected, then the defibrillator delivers the appropriate electric shock through the patient's body, and thus through the heart.
A problem is that compliance by the patient is often not full. While the patient has the system, they often do not wear it because they find it cumbersome and uncomfortable. The issue of improving compliance has been addressed, for example in US Patent Application No. 20120283794.
A root of the discomfort is from the fact that the electrodes of the wearable system have to be making good electrical contact continuously with the patient's skin, so that the patient's ECG can be monitored continuously. The problem has been addressed, for example in U.S. Pat. No. 6,546,285, titled LONG TERM WEAR ELECTRODE FOR DEFIBRILLATION SYSTEM. The latter patent teaches, among other things, to move the electrodes to different places on the patient's skin at different times, and/or to use a hydrogel for the electrodes that includes a therapeutic agent which promotes skin health.